Place asparagus on a baking sheet. Drizzle with olive oil, and toss to coat. Arrange asparagus spears in a single layer. Spread Parmesan cheese over asparagus, and season with freshly ground black pepper.
Bake 12 to 15 minutes in the preheated oven, until cheese is melted and asparagus is tender but crisp. Serve immediately on warm plates, sprinkling with balsamic vinegar to taste.
